i. Antiarrhythmics (e.g. amiodarone, disopyramide, dofetilide, ibutilide, procainamide, quinidine, hydroquinidine, sotalol) ii. Neuroleptics (e.g. phenothiazines, sertindole, sultopride, chlorpromazine, haloperidol, mesoridazine, pimozide, or thioridazine) iii. Antidepressive agents, certain antimicrobial agents, including agents of the following classes macrolides (e.g. erythromycin, clarithromycin), fluoroquinolones (e.g. moxifloxacin, sparfloxacin), imidazole and triazole antifungal agents, and also pentamidine and saquinavir iv. Certain non-sedating antihistamines (e.g. terfenadine, astemizole, mizolastine), cisapride, droperidol, domperidone, bepridil, diphemanil, probucol, levomethadyl, methadone, vinca alkaloids, arsenic trioxide